3 bool "64-bit kernel" if ARCH = "x86"
4 default ARCH = "x86_64"
6 Say yes to build a 64-bit kernel - formerly known as x86_64
7 Say no to build a 32-bit kernel - formerly known as i386
18 select HAVE_AOUT if X86_32
21 select HAVE_UNSTABLE_SCHED_CLOCK
24 select HAVE_PERF_EVENTS if (!M386 && !M486)
26 select HAVE_IOREMAP_PROT
29 select ARCH_WANT_OPTIONAL_GPIOLIB
30 select ARCH_WANT_FRAME_POINTERS
32 select HAVE_KRETPROBES
34 select HAVE_FTRACE_MCOUNT_RECORD
35 select HAVE_C_RECORDMCOUNT
36 select HAVE_DYNAMIC_FTRACE
37 select HAVE_FUNCTION_TRACER
38 select HAVE_FUNCTION_GRAPH_TRACER
39 select HAVE_FUNCTION_GRAPH_FP_TEST
40 select HAVE_FUNCTION_TRACE_MCOUNT_TEST
41 select HAVE_FTRACE_NMI_ENTER if DYNAMIC_FTRACE
42 select HAVE_SYSCALL_TRACEPOINTS
45 select HAVE_ARCH_TRACEHOOK
46 select HAVE_GENERIC_DMA_COHERENT if X86_32
47 select HAVE_EFFICIENT_UNALIGNED_ACCESS
48 select USER_STACKTRACE_SUPPORT
49 select HAVE_REGS_AND_STACK_ACCESS_API
50 select HAVE_DMA_API_DEBUG
51 select HAVE_KERNEL_GZIP
52 select HAVE_KERNEL_BZIP2
53 select HAVE_KERNEL_LZMA
54 select HAVE_KERNEL_LZO
55 select HAVE_HW_BREAKPOINT
56 select HAVE_MIXED_BREAKPOINTS_REGS
58 select HAVE_PERF_EVENTS_NMI
60 select HAVE_ARCH_KMEMCHECK
61 select HAVE_USER_RETURN_NOTIFIER
62 select HAVE_ARCH_JUMP_LABEL
63 select HAVE_TEXT_POKE_SMP
64 select HAVE_GENERIC_HARDIRQS
65 select HAVE_SPARSE_IRQ
66 select GENERIC_IRQ_PROBE
67 select GENERIC_PENDING_IRQ if SMP
69 config INSTRUCTION_DECODER
70 def_bool (KPROBES || PERF_EVENTS)
74 default "elf32-i386" if X86_32
75 default "elf64-x86-64" if X86_64
79 default "arch/x86/configs/i386_defconfig" if X86_32
80 default "arch/x86/configs/x86_64_defconfig" if X86_64
82 config GENERIC_CMOS_UPDATE
85 config CLOCKSOURCE_WATCHDOG
88 config GENERIC_CLOCKEVENTS
91 config GENERIC_CLOCKEVENTS_BROADCAST
93 depends on X86_64 || (X86_32 && X86_LOCAL_APIC)
95 config LOCKDEP_SUPPORT
98 config STACKTRACE_SUPPORT
101 config HAVE_LATENCYTOP_SUPPORT
113 config NEED_DMA_MAP_STATE
114 def_bool (X86_64 || DMAR || DMA_API_DEBUG)
116 config NEED_SG_DMA_LENGTH
119 config GENERIC_ISA_DMA
128 select GENERIC_BUG_RELATIVE_POINTERS if X86_64
130 config GENERIC_BUG_RELATIVE_POINTERS
133 config GENERIC_HWEIGHT
139 config ARCH_MAY_HAVE_PC_FDC
142 config RWSEM_GENERIC_SPINLOCK
145 config RWSEM_XCHGADD_ALGORITHM
148 config ARCH_HAS_CPU_IDLE_WAIT
151 config GENERIC_CALIBRATE_DELAY
154 config GENERIC_TIME_VSYSCALL
158 config ARCH_HAS_CPU_RELAX
161 config ARCH_HAS_DEFAULT_IDLE
164 config ARCH_HAS_CACHE_LINE_SIZE
167 config HAVE_SETUP_PER_CPU_AREA
170 config NEED_PER_CPU_EMBED_FIRST_CHUNK
173 config NEED_PER_CPU_PAGE_FIRST_CHUNK
176 config HAVE_CPUMASK_OF_CPU_MAP
179 config ARCH_HIBERNATION_POSSIBLE
182 config ARCH_SUSPEND_POSSIBLE
189 config ARCH_POPULATES_NODE_MAP
196 config ARCH_SUPPORTS_OPTIMIZED_INLINING
199 config ARCH_SUPPORTS_DEBUG_PAGEALLOC
202 config HAVE_INTEL_TXT
204 depends on EXPERIMENTAL && DMAR && ACPI
206 config USE_GENERIC_SMP_HELPERS
212 depends on X86_32 && SMP
216 depends on X86_64 && SMP
222 config X86_TRAMPOLINE
224 depends on SMP || (64BIT && ACPI_SLEEP)
226 config X86_32_LAZY_GS
228 depends on X86_32 && !CC_STACKPROTECTOR
230 config ARCH_HWEIGHT_CFLAGS
232 default "-fcall-saved-ecx -fcall-saved-edx" if X86_32
233 default "-fcall-saved-rdi -fcall-saved-rsi -fcall-saved-rdx -fcall-saved-rcx -fcall-saved-r8 -fcall-saved-r9 -fcall-saved-r10 -fcall-saved-r11" if X86_64
238 config ARCH_CPU_PROBE_RELEASE
240 depends on HOTPLUG_CPU
242 source "init/Kconfig"
243 source "kernel/Kconfig.freezer"
245 menu "Processor type and features"
247 source "kernel/time/Kconfig"
250 bool "Symmetric multi-processing support"
252 This enables support for systems with more than one CPU. If you have
253 a system with only one CPU, like most personal computers, say N. If
254 you have a system with more than one CPU, say Y.
256 If you say N here, the kernel will run on single and multiprocessor
257 machines, but will use only one CPU of a multiprocessor machine. If
258 you say Y here, the kernel will run on many, but not all,
259 singleprocessor machines. On a singleprocessor machine, the kernel
260 will run faster if you say N here.
262 Note that if you say Y here and choose architecture "586" or
263 "Pentium" under "Processor family", the kernel will not work on 486
264 architectures. Similarly, multiprocessor kernels for the "PPro"
265 architecture may not work on all Pentium based boards.
267 People using multiprocessor machines who say Y here should also say
268 Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
269 Management" code will be disabled if you say Y here.
271 See also <file:Documentation/i386/IO-APIC.txt>,
272 <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO available at
273 <http://www.tldp.org/docs.html#howto>.
275 If you don't know what to do here, say N.
278 bool "Support x2apic"
279 depends on X86_LOCAL_APIC && X86_64 && INTR_REMAP
281 This enables x2apic support on CPUs that have this feature.
283 This allows 32-bit apic IDs (so it can support very large systems),
284 and accesses the local apic via MSRs not via mmio.
286 If you don't know what to do here, say N.
289 bool "Enable MPS table" if ACPI
291 depends on X86_LOCAL_APIC
293 For old smp systems that do not have proper acpi support. Newer systems
294 (esp with 64bit cpus) with acpi support, MADT and DSDT will override it
297 bool "Support for big SMP systems with more than 8 CPUs"
298 depends on X86_32 && SMP
300 This option is needed for the systems that have more than 8 CPUs
303 config X86_EXTENDED_PLATFORM
304 bool "Support for extended (non-PC) x86 platforms"
307 If you disable this option then the kernel will only support
308 standard PC platforms. (which covers the vast majority of
311 If you enable this option then you'll be able to select support
312 for the following (non-PC) 32 bit x86 platforms:
316 SGI 320/540 (Visual Workstation)
317 Summit/EXA (IBM x440)
318 Unisys ES7000 IA32 series
319 Moorestown MID devices
321 If you have one of these systems, or if you want to build a
322 generic distribution kernel, say Y here - otherwise say N.
326 config X86_EXTENDED_PLATFORM
327 bool "Support for extended (non-PC) x86 platforms"
330 If you disable this option then the kernel will only support
331 standard PC platforms. (which covers the vast majority of
334 If you enable this option then you'll be able to select support
335 for the following (non-PC) 64 bit x86 platforms:
339 If you have one of these systems, or if you want to build a
340 generic distribution kernel, say Y here - otherwise say N.
342 # This is an alphabetically sorted list of 64 bit extended platforms
343 # Please maintain the alphabetic order if and when there are additions
347 select PARAVIRT_GUEST
349 depends on X86_64 && PCI
350 depends on X86_EXTENDED_PLATFORM
352 Support for ScaleMP vSMP systems. Say 'Y' here if this kernel is
353 supposed to run on these EM64T-based machines. Only choose this option
354 if you have one of these machines.
357 bool "SGI Ultraviolet"
359 depends on X86_EXTENDED_PLATFORM
361 depends on X86_X2APIC
363 This option is needed in order to support SGI Ultraviolet systems.
364 If you don't have one of these, you should say N here.
366 # Following is an alphabetically sorted list of 32 bit extended platforms
367 # Please maintain the alphabetic order if and when there are additions
372 depends on X86_EXTENDED_PLATFORM
374 Select this for an AMD Elan processor.
376 Do not use this option for K6/Athlon/Opteron processors!
378 If unsure, choose "PC-compatible" instead.
381 bool "CE4100 TV platform"
383 depends on PCI_GODIRECT
385 depends on X86_EXTENDED_PLATFORM
386 select X86_REBOOTFIXUPS
388 Select for the Intel CE media processor (CE4100) SOC.
389 This option compiles in support for the CE4100 SOC for settop
390 boxes and media devices.
393 bool "Moorestown MID platform"
397 depends on X86_EXTENDED_PLATFORM
398 depends on X86_IO_APIC
404 Moorestown is Intel's Low Power Intel Architecture (LPIA) based Moblin
405 Internet Device(MID) platform. Moorestown consists of two chips:
406 Lincroft (CPU core, graphics, and memory controller) and Langwell IOH.
407 Unlike standard x86 PCs, Moorestown does not have many legacy devices
408 nor standard legacy replacement devices/features. e.g. Moorestown does
409 not contain i8259, i8254, HPET, legacy BIOS, most of the io ports.
412 bool "RDC R-321x SoC"
414 depends on X86_EXTENDED_PLATFORM
416 select X86_REBOOTFIXUPS
418 This option is needed for RDC R-321x system-on-chip, also known
420 If you don't have one of these chips, you should say N here.
422 config X86_32_NON_STANDARD
423 bool "Support non-standard 32-bit SMP architectures"
424 depends on X86_32 && SMP
425 depends on X86_EXTENDED_PLATFORM
427 This option compiles in the NUMAQ, Summit, bigsmp, ES7000, default
428 subarchitectures. It is intended for a generic binary kernel.
429 if you select them all, kernel will probe it one by one. and will
432 # Alphabetically sorted list of Non standard 32 bit platforms
435 bool "NUMAQ (IBM/Sequent)"
436 depends on X86_32_NON_STANDARD
441 This option is used for getting Linux to run on a NUMAQ (IBM/Sequent)
442 NUMA multiquad box. This changes the way that processors are
443 bootstrapped, and uses Clustered Logical APIC addressing mode instead
444 of Flat Logical. You will need a new lynxer.elf file to flash your
445 firmware with - send email to <Martin.Bligh@us.ibm.com>.
447 config X86_SUPPORTS_MEMORY_FAILURE
449 # MCE code calls memory_failure():
451 # On 32-bit this adds too big of NODES_SHIFT and we run out of page flags:
452 depends on !X86_NUMAQ
453 # On 32-bit SPARSEMEM adds too big of SECTIONS_WIDTH:
454 depends on X86_64 || !SPARSEMEM
455 select ARCH_SUPPORTS_MEMORY_FAILURE
458 bool "SGI 320/540 (Visual Workstation)"
459 depends on X86_32 && PCI && X86_MPPARSE && PCI_GODIRECT
460 depends on X86_32_NON_STANDARD
462 The SGI Visual Workstation series is an IA32-based workstation
463 based on SGI systems chips with some legacy PC hardware attached.
465 Say Y here to create a kernel to run on the SGI 320 or 540.
467 A kernel compiled for the Visual Workstation will run on general
468 PCs as well. See <file:Documentation/sgi-visws.txt> for details.
471 bool "Summit/EXA (IBM x440)"
472 depends on X86_32_NON_STANDARD
474 This option is needed for IBM systems that use the Summit/EXA chipset.
475 In particular, it is needed for the x440.
478 bool "Unisys ES7000 IA32 series"
479 depends on X86_32_NON_STANDARD && X86_BIGSMP
481 Support for Unisys ES7000 systems. Say 'Y' here if this kernel is
482 supposed to run on an IA32-based Unisys ES7000 system.
484 config SCHED_OMIT_FRAME_POINTER
486 prompt "Single-depth WCHAN output"
489 Calculate simpler /proc/<PID>/wchan values. If this option
490 is disabled then wchan values will recurse back to the
491 caller function. This provides more accurate wchan values,
492 at the expense of slightly more scheduling overhead.
494 If in doubt, say "Y".
496 menuconfig PARAVIRT_GUEST
497 bool "Paravirtualized guest support"
499 Say Y here to get to see options related to running Linux under
500 various hypervisors. This option alone does not add any kernel code.
502 If you say N, all options in this submenu will be skipped and disabled.
506 source "arch/x86/xen/Kconfig"
509 bool "KVM paravirtualized clock"
511 select PARAVIRT_CLOCK
513 Turning on this option will allow you to run a paravirtualized clock
514 when running over the KVM hypervisor. Instead of relying on a PIT
515 (or probably other) emulation by the underlying device model, the host
516 provides the guest with timing infrastructure such as time of day, and
520 bool "KVM Guest support"
523 This option enables various optimizations for running under the KVM
526 source "arch/x86/lguest/Kconfig"
529 bool "Enable paravirtualization code"
531 This changes the kernel so it can modify itself when it is run
532 under a hypervisor, potentially improving performance significantly
533 over full virtualization. However, when run without a hypervisor
534 the kernel is theoretically slower and slightly larger.
536 config PARAVIRT_SPINLOCKS
537 bool "Paravirtualization layer for spinlocks"
538 depends on PARAVIRT && SMP && EXPERIMENTAL
540 Paravirtualized spinlocks allow a pvops backend to replace the
541 spinlock implementation with something virtualization-friendly
542 (for example, block the virtual CPU rather than spinning).
544 Unfortunately the downside is an up to 5% performance hit on
545 native kernels, with various workloads.
547 If you are unsure how to answer this question, answer N.
549 config PARAVIRT_CLOCK
554 config PARAVIRT_DEBUG
555 bool "paravirt-ops debugging"
556 depends on PARAVIRT && DEBUG_KERNEL
558 Enable to debug paravirt_ops internals. Specifically, BUG if
559 a paravirt_op is missing when it is called.
567 This option adds a kernel parameter 'memtest', which allows memtest
569 memtest=0, mean disabled; -- default
570 memtest=1, mean do 1 test pattern;
572 memtest=4, mean do 4 test patterns.
573 If you are unsure how to answer this question, answer N.
575 config X86_SUMMIT_NUMA
577 depends on X86_32 && NUMA && X86_32_NON_STANDARD
579 config X86_CYCLONE_TIMER
581 depends on X86_32_NON_STANDARD
583 source "arch/x86/Kconfig.cpu"
587 prompt "HPET Timer Support" if X86_32
589 Use the IA-PC HPET (High Precision Event Timer) to manage
590 time in preference to the PIT and RTC, if a HPET is
592 HPET is the next generation timer replacing legacy 8254s.
593 The HPET provides a stable time base on SMP
594 systems, unlike the TSC, but it is more expensive to access,
595 as it is off-chip. You can find the HPET spec at
596 <http://www.intel.com/hardwaredesign/hpetspec_1.pdf>.
598 You can safely choose Y here. However, HPET will only be
599 activated if the platform and the BIOS support this feature.
600 Otherwise the 8254 will be used for timing services.
602 Choose N to continue using the legacy 8254 timer.
604 config HPET_EMULATE_RTC
606 depends on HPET_TIMER && (RTC=y || RTC=m || RTC_DRV_CMOS=m || RTC_DRV_CMOS=y)
610 prompt "Langwell APB Timer Support" if X86_MRST
612 APB timer is the replacement for 8254, HPET on X86 MID platforms.
613 The APBT provides a stable time base on SMP
614 systems, unlike the TSC, but it is more expensive to access,
615 as it is off-chip. APB timers are always running regardless of CPU
616 C states, they are used as per CPU clockevent device when possible.
618 # Mark as embedded because too many people got it wrong.
619 # The code disables itself when not needed.
622 bool "Enable DMI scanning" if EMBEDDED
624 Enabled scanning of DMI to identify machine quirks. Say Y
625 here unless you have verified that your setup is not
626 affected by entries in the DMI blacklist. Required by PNP
630 bool "GART IOMMU support" if EMBEDDED
633 depends on X86_64 && PCI && AMD_NB
635 Support for full DMA access of devices with 32bit memory access only
636 on systems with more than 3GB. This is usually needed for USB,
637 sound, many IDE/SATA chipsets and some other devices.
638 Provides a driver for the AMD Athlon64/Opteron/Turion/Sempron GART
639 based hardware IOMMU and a software bounce buffer based IOMMU used
640 on Intel systems and as fallback.
641 The code is only active when needed (enough memory and limited
642 device) unless CONFIG_IOMMU_DEBUG or iommu=force is specified
646 bool "IBM Calgary IOMMU support"
648 depends on X86_64 && PCI && EXPERIMENTAL
650 Support for hardware IOMMUs in IBM's xSeries x366 and x460
651 systems. Needed to run systems with more than 3GB of memory
652 properly with 32-bit PCI devices that do not support DAC
653 (Double Address Cycle). Calgary also supports bus level
654 isolation, where all DMAs pass through the IOMMU. This
655 prevents them from going anywhere except their intended
656 destination. This catches hard-to-find kernel bugs and
657 mis-behaving drivers and devices that do not use the DMA-API
658 properly to set up their DMA buffers. The IOMMU can be
659 turned off at boot time with the iommu=off parameter.
660 Normally the kernel will make the right choice by itself.
663 config CALGARY_IOMMU_ENABLED_BY_DEFAULT
665 prompt "Should Calgary be enabled by default?"
666 depends on CALGARY_IOMMU
668 Should Calgary be enabled by default? if you choose 'y', Calgary
669 will be used (if it exists). If you choose 'n', Calgary will not be
670 used even if it exists. If you choose 'n' and would like to use
671 Calgary anyway, pass 'iommu=calgary' on the kernel command line.
675 bool "AMD IOMMU support"
678 depends on X86_64 && PCI && ACPI
680 With this option you can enable support for AMD IOMMU hardware in
681 your system. An IOMMU is a hardware component which provides
682 remapping of DMA memory accesses from devices. With an AMD IOMMU you
683 can isolate the the DMA memory of different devices and protect the
684 system from misbehaving device drivers or hardware.
686 You can find out if your system has an AMD IOMMU if you look into
687 your BIOS for an option to enable it or if you have an IVRS ACPI
690 config AMD_IOMMU_STATS
691 bool "Export AMD IOMMU statistics to debugfs"
695 This option enables code in the AMD IOMMU driver to collect various
696 statistics about whats happening in the driver and exports that
697 information to userspace via debugfs.
700 # need this always selected by IOMMU for the VIA workaround
704 Support for software bounce buffers used on x86-64 systems
705 which don't have a hardware IOMMU (e.g. the current generation
706 of Intel's x86-64 CPUs). Using this PCI devices which can only
707 access 32-bits of memory can be used on systems with more than
708 3 GB of memory. If unsure, say Y.
711 def_bool (CALGARY_IOMMU || GART_IOMMU || SWIOTLB || AMD_IOMMU)
714 def_bool (AMD_IOMMU || DMAR)
717 bool "Enable Maximum number of SMP Processors and NUMA Nodes"
718 depends on X86_64 && SMP && DEBUG_KERNEL && EXPERIMENTAL
719 select CPUMASK_OFFSTACK
721 Enable maximum number of CPUS and NUMA Nodes for this architecture.
725 int "Maximum number of CPUs" if SMP && !MAXSMP
726 range 2 8 if SMP && X86_32 && !X86_BIGSMP
727 range 2 512 if SMP && !MAXSMP
729 default "4096" if MAXSMP
730 default "32" if SMP && (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP || X86_ES7000)
733 This allows you to specify the maximum number of CPUs which this
734 kernel will support. The maximum supported value is 512 and the
735 minimum value which makes sense is 2.
737 This is purely to save memory - each supported CPU adds
738 approximately eight kilobytes to the kernel image.
741 bool "SMT (Hyperthreading) scheduler support"
744 SMT scheduler support improves the CPU scheduler's decision making
745 when dealing with Intel Pentium 4 chips with HyperThreading at a
746 cost of slightly increased overhead in some places. If unsure say
751 prompt "Multi-core scheduler support"
754 Multi-core scheduler support improves the CPU scheduler's decision
755 making when dealing with multi-core CPU chips at a cost of slightly
756 increased overhead in some places. If unsure say N here.
758 config IRQ_TIME_ACCOUNTING
759 bool "Fine granularity task level IRQ time accounting"
762 Select this option to enable fine granularity task irq time
763 accounting. This is done by reading a timestamp on each
764 transitions between softirq and hardirq state, so there can be a
765 small performance impact.
767 If in doubt, say N here.
769 source "kernel/Kconfig.preempt"
772 bool "Local APIC support on uniprocessors"
773 depends on X86_32 && !SMP && !X86_32_NON_STANDARD
775 A local APIC (Advanced Programmable Interrupt Controller) is an
776 integrated interrupt controller in the CPU. If you have a single-CPU
777 system which has a processor with a local APIC, you can say Y here to
778 enable and use it. If you say Y here even though your machine doesn't
779 have a local APIC, then the kernel will still run with no slowdown at
780 all. The local APIC supports CPU-generated self-interrupts (timer,
781 performance counters), and the NMI watchdog which detects hard
785 bool "IO-APIC support on uniprocessors"
786 depends on X86_UP_APIC
788 An IO-APIC (I/O Advanced Programmable Interrupt Controller) is an
789 SMP-capable replacement for PC-style interrupt controllers. Most
790 SMP systems and many recent uniprocessor systems have one.
792 If you have a single-CPU system with an IO-APIC, you can say Y here
793 to use it. If you say Y here even though your machine doesn't have
794 an IO-APIC, then the kernel will still run with no slowdown at all.
796 config X86_LOCAL_APIC
798 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
802 depends on X86_64 || SMP || X86_32_NON_STANDARD || X86_UP_APIC
804 config X86_VISWS_APIC
806 depends on X86_32 && X86_VISWS
808 config X86_REROUTE_FOR_BROKEN_BOOT_IRQS
809 bool "Reroute for broken boot IRQs"
810 depends on X86_IO_APIC
812 This option enables a workaround that fixes a source of
813 spurious interrupts. This is recommended when threaded
814 interrupt handling is used on systems where the generation of
815 superfluous "boot interrupts" cannot be disabled.
817 Some chipsets generate a legacy INTx "boot IRQ" when the IRQ
818 entry in the chipset's IO-APIC is masked (as, e.g. the RT
819 kernel does during interrupt handling). On chipsets where this
820 boot IRQ generation cannot be disabled, this workaround keeps
821 the original IRQ line masked so that only the equivalent "boot
822 IRQ" is delivered to the CPUs. The workaround also tells the
823 kernel to set up the IRQ handler on the boot IRQ line. In this
824 way only one interrupt is delivered to the kernel. Otherwise
825 the spurious second interrupt may cause the kernel to bring
826 down (vital) interrupt lines.
828 Only affects "broken" chipsets. Interrupt sharing may be
829 increased on these systems.
832 bool "Machine Check / overheating reporting"
834 Machine Check support allows the processor to notify the
835 kernel if it detects a problem (e.g. overheating, data corruption).
836 The action the kernel takes depends on the severity of the problem,
837 ranging from warning messages to halting the machine.
841 prompt "Intel MCE features"
842 depends on X86_MCE && X86_LOCAL_APIC
844 Additional support for intel specific MCE features such as
849 prompt "AMD MCE features"
850 depends on X86_MCE && X86_LOCAL_APIC
852 Additional support for AMD specific MCE features such as
853 the DRAM Error Threshold.
855 config X86_ANCIENT_MCE
856 bool "Support for old Pentium 5 / WinChip machine checks"
857 depends on X86_32 && X86_MCE
859 Include support for machine check handling on old Pentium 5 or WinChip
860 systems. These typically need to be enabled explicitely on the command
863 config X86_MCE_THRESHOLD
864 depends on X86_MCE_AMD || X86_MCE_INTEL
867 config X86_MCE_INJECT
869 tristate "Machine check injector support"
871 Provide support for injecting machine checks for testing purposes.
872 If you don't know what a machine check is and you don't do kernel
873 QA it is safe to say n.
875 config X86_THERMAL_VECTOR
877 depends on X86_MCE_INTEL
880 bool "Enable VM86 support" if EMBEDDED
884 This option is required by programs like DOSEMU to run 16-bit legacy
885 code on X86 processors. It also may be needed by software like
886 XFree86 to initialize some video cards via BIOS. Disabling this
887 option saves about 6k.
890 tristate "Toshiba Laptop support"
893 This adds a driver to safely access the System Management Mode of
894 the CPU on Toshiba portables with a genuine Toshiba BIOS. It does
895 not work on models with a Phoenix BIOS. The System Management Mode
896 is used to set the BIOS and power saving options on Toshiba portables.
898 For information on utilities to make use of this driver see the
899 Toshiba Linux utilities web site at:
900 <http://www.buzzard.org.uk/toshiba/>.
902 Say Y if you intend to run this kernel on a Toshiba portable.
906 tristate "Dell laptop support"
908 This adds a driver to safely access the System Management Mode
909 of the CPU on the Dell Inspiron 8000. The System Management Mode
910 is used to read cpu temperature and cooling fan status and to
911 control the fans on the I8K portables.
913 This driver has been tested only on the Inspiron 8000 but it may
914 also work with other Dell laptops. You can force loading on other
915 models by passing the parameter `force=1' to the module. Use at
918 For information on utilities to make use of this driver see the
919 I8K Linux utilities web site at:
920 <http://people.debian.org/~dz/i8k/>
922 Say Y if you intend to run this kernel on a Dell Inspiron 8000.
925 config X86_REBOOTFIXUPS
926 bool "Enable X86 board specific fixups for reboot"
929 This enables chipset and/or board specific fixups to be done
930 in order to get reboot to work correctly. This is only needed on
931 some combinations of hardware and BIOS. The symptom, for which
932 this config is intended, is when reboot ends with a stalled/hung
935 Currently, the only fixup is for the Geode machines using
936 CS5530A and CS5536 chipsets and the RDC R-321x SoC.
938 Say Y if you want to enable the fixup. Currently, it's safe to
939 enable this option even if you don't need it.
943 tristate "/dev/cpu/microcode - microcode support"
946 If you say Y here, you will be able to update the microcode on
947 certain Intel and AMD processors. The Intel support is for the
948 IA32 family, e.g. Pentium Pro, Pentium II, Pentium III,
949 Pentium 4, Xeon etc. The AMD support is for family 0x10 and
950 0x11 processors, e.g. Opteron, Phenom and Turion 64 Ultra.
951 You will obviously need the actual microcode binary data itself
952 which is not shipped with the Linux kernel.
954 This option selects the general module only, you need to select
955 at least one vendor specific module as well.
957 To compile this driver as a module, choose M here: the
958 module will be called microcode.
960 config MICROCODE_INTEL
961 bool "Intel microcode patch loading support"
966 This options enables microcode patch loading support for Intel
969 For latest news and information on obtaining all the required
970 Intel ingredients for this driver, check:
971 <http://www.urbanmyth.org/microcode/>.
974 bool "AMD microcode patch loading support"
978 If you select this option, microcode patch loading support for AMD
979 processors will be enabled.
981 config MICROCODE_OLD_INTERFACE
986 tristate "/dev/cpu/*/msr - Model-specific register support"
988 This device gives privileged processes access to the x86
989 Model-Specific Registers (MSRs). It is a character device with
990 major 202 and minors 0 to 31 for /dev/cpu/0/msr to /dev/cpu/31/msr.
991 MSR accesses are directed to a specific CPU on multi-processor
995 tristate "/dev/cpu/*/cpuid - CPU information support"
997 This device gives processes access to the x86 CPUID instruction to
998 be executed on a specific processor. It is a character device
999 with major 203 and minors 0 to 31 for /dev/cpu/0/cpuid to
1003 prompt "High Memory Support"
1004 default HIGHMEM64G if X86_NUMAQ
1010 depends on !X86_NUMAQ
1012 Linux can use up to 64 Gigabytes of physical memory on x86 systems.
1013 However, the address space of 32-bit x86 processors is only 4
1014 Gigabytes large. That means that, if you have a large amount of
1015 physical memory, not all of it can be "permanently mapped" by the
1016 kernel. The physical memory that's not permanently mapped is called
1019 If you are compiling a kernel which will never run on a machine with
1020 more than 1 Gigabyte total physical RAM, answer "off" here (default
1021 choice and suitable for most users). This will result in a "3GB/1GB"
1022 split: 3GB are mapped so that each process sees a 3GB virtual memory
1023 space and the remaining part of the 4GB virtual memory space is used
1024 by the kernel to permanently map as much physical memory as
1027 If the machine has between 1 and 4 Gigabytes physical RAM, then
1030 If more than 4 Gigabytes is used then answer "64GB" here. This
1031 selection turns Intel PAE (Physical Address Extension) mode on.
1032 PAE implements 3-level paging on IA32 processors. PAE is fully
1033 supported by Linux, PAE mode is implemented on all recent Intel
1034 processors (Pentium Pro and better). NOTE: If you say "64GB" here,
1035 then the kernel will not boot on CPUs that don't support PAE!
1037 The actual amount of total physical memory will either be
1038 auto detected or can be forced by using a kernel command line option
1039 such as "mem=256M". (Try "man bootparam" or see the documentation of
1040 your boot loader (lilo or loadlin) about how to pass options to the
1041 kernel at boot time.)
1043 If unsure, say "off".
1047 depends on !X86_NUMAQ
1049 Select this if you have a 32-bit processor and between 1 and 4
1050 gigabytes of physical RAM.
1054 depends on !M386 && !M486
1057 Select this if you have a 32-bit processor and more than 4
1058 gigabytes of physical RAM.
1063 depends on EXPERIMENTAL
1064 prompt "Memory split" if EMBEDDED
1068 Select the desired split between kernel and user memory.
1070 If the address range available to the kernel is less than the
1071 physical memory installed, the remaining memory will be available
1072 as "high memory". Accessing high memory is a little more costly
1073 than low memory, as it needs to be mapped into the kernel first.
1074 Note that increasing the kernel address space limits the range
1075 available to user programs, making the address space there
1076 tighter. Selecting anything other than the default 3G/1G split
1077 will also likely make your kernel incompatible with binary-only
1080 If you are not absolutely sure what you are doing, leave this
1084 bool "3G/1G user/kernel split"
1085 config VMSPLIT_3G_OPT
1087 bool "3G/1G user/kernel split (for full 1G low memory)"
1089 bool "2G/2G user/kernel split"
1090 config VMSPLIT_2G_OPT
1092 bool "2G/2G user/kernel split (for full 2G low memory)"
1094 bool "1G/3G user/kernel split"
1099 default 0xB0000000 if VMSPLIT_3G_OPT
1100 default 0x80000000 if VMSPLIT_2G
1101 default 0x78000000 if VMSPLIT_2G_OPT
1102 default 0x40000000 if VMSPLIT_1G
1108 depends on X86_32 && (HIGHMEM64G || HIGHMEM4G)
1111 bool "PAE (Physical Address Extension) Support"
1112 depends on X86_32 && !HIGHMEM4G
1114 PAE is required for NX support, and furthermore enables
1115 larger swapspace support for non-overcommit purposes. It
1116 has the cost of more pagetable lookup overhead, and also
1117 consumes more pagetable space per process.
1119 config ARCH_PHYS_ADDR_T_64BIT
1120 def_bool X86_64 || X86_PAE
1122 config ARCH_DMA_ADDR_T_64BIT
1123 def_bool X86_64 || HIGHMEM64G
1125 config DIRECT_GBPAGES
1126 bool "Enable 1GB pages for kernel pagetables" if EMBEDDED
1130 Allow the kernel linear mapping to use 1GB pages on CPUs that
1131 support it. This can improve the kernel's performance a tiny bit by
1132 reducing TLB pressure. If in doubt, say "Y".
1134 # Common NUMA Features
1136 bool "Numa Memory Allocation and Scheduler Support"
1138 depends on X86_64 || (X86_32 && HIGHMEM64G && (X86_NUMAQ || X86_BIGSMP || X86_SUMMIT && ACPI) && EXPERIMENTAL)
1139 default y if (X86_NUMAQ || X86_SUMMIT || X86_BIGSMP)
1141 Enable NUMA (Non Uniform Memory Access) support.
1143 The kernel will try to allocate memory used by a CPU on the
1144 local memory controller of the CPU and add some more
1145 NUMA awareness to the kernel.
1147 For 64-bit this is recommended if the system is Intel Core i7
1148 (or later), AMD Opteron, or EM64T NUMA.
1150 For 32-bit this is only needed on (rare) 32-bit-only platforms
1151 that support NUMA topologies, such as NUMAQ / Summit, or if you
1152 boot a 32-bit kernel on a 64-bit NUMA platform.
1154 Otherwise, you should say N.
1156 comment "NUMA (Summit) requires SMP, 64GB highmem support, ACPI"
1157 depends on X86_32 && X86_SUMMIT && (!HIGHMEM64G || !ACPI)
1161 prompt "Old style AMD Opteron NUMA detection"
1162 depends on X86_64 && NUMA && PCI
1164 Enable K8 NUMA node topology detection. You should say Y here if
1165 you have a multi processor AMD K8 system. This uses an old
1166 method to read the NUMA configuration directly from the builtin
1167 Northbridge of Opteron. It is recommended to use X86_64_ACPI_NUMA
1168 instead, which also takes priority if both are compiled in.
1170 config X86_64_ACPI_NUMA
1172 prompt "ACPI NUMA detection"
1173 depends on X86_64 && NUMA && ACPI && PCI
1176 Enable ACPI SRAT based node topology detection.
1178 # Some NUMA nodes have memory ranges that span
1179 # other nodes. Even though a pfn is valid and
1180 # between a node's start and end pfns, it may not
1181 # reside on that node. See memmap_init_zone()
1183 config NODES_SPAN_OTHER_NODES
1185 depends on X86_64_ACPI_NUMA
1188 bool "NUMA emulation"
1189 depends on X86_64 && NUMA
1191 Enable NUMA emulation. A flat machine will be split
1192 into virtual nodes when booted with "numa=fake=N", where N is the
1193 number of nodes. This is only useful for debugging.
1196 int "Maximum NUMA Nodes (as a power of 2)" if !MAXSMP
1198 default "10" if MAXSMP
1199 default "6" if X86_64
1200 default "4" if X86_NUMAQ
1202 depends on NEED_MULTIPLE_NODES
1204 Specify the maximum number of NUMA Nodes available on the target
1205 system. Increases memory reserved to accommodate various tables.
1207 config HAVE_ARCH_BOOTMEM
1209 depends on X86_32 && NUMA
1211 config ARCH_HAVE_MEMORY_PRESENT
1213 depends on X86_32 && DISCONTIGMEM
1215 config NEED_NODE_MEMMAP_SIZE
1217 depends on X86_32 && (DISCONTIGMEM || SPARSEMEM)
1219 config HAVE_ARCH_ALLOC_REMAP
1221 depends on X86_32 && NUMA
1223 config ARCH_FLATMEM_ENABLE
1225 depends on X86_32 && ARCH_SELECT_MEMORY_MODEL && !NUMA
1227 config ARCH_DISCONTIGMEM_ENABLE
1229 depends on NUMA && X86_32
1231 config ARCH_DISCONTIGMEM_DEFAULT
1233 depends on NUMA && X86_32
1235 config ARCH_PROC_KCORE_TEXT
1237 depends on X86_64 && PROC_KCORE
1239 config ARCH_SPARSEMEM_DEFAULT
1243 config ARCH_SPARSEMEM_ENABLE
1245 depends on X86_64 || NUMA || (EXPERIMENTAL && X86_32) || X86_32_NON_STANDARD
1246 select SPARSEMEM_STATIC if X86_32
1247 select SPARSEMEM_VMEMMAP_ENABLE if X86_64
1249 config ARCH_SELECT_MEMORY_MODEL
1251 depends on ARCH_SPARSEMEM_ENABLE
1253 config ARCH_MEMORY_PROBE
1255 depends on MEMORY_HOTPLUG
1257 config ILLEGAL_POINTER_VALUE
1260 default 0xdead000000000000 if X86_64
1265 bool "Allocate 3rd-level pagetables from highmem"
1268 The VM uses one page table entry for each page of physical memory.
1269 For systems with a lot of RAM, this can be wasteful of precious
1270 low memory. Setting this option will put user-space page table
1271 entries in high memory.
1273 config X86_CHECK_BIOS_CORRUPTION
1274 bool "Check for low memory corruption"
1276 Periodically check for memory corruption in low memory, which
1277 is suspected to be caused by BIOS. Even when enabled in the
1278 configuration, it is disabled at runtime. Enable it by
1279 setting "memory_corruption_check=1" on the kernel command
1280 line. By default it scans the low 64k of memory every 60
1281 seconds; see the memory_corruption_check_size and
1282 memory_corruption_check_period parameters in
1283 Documentation/kernel-parameters.txt to adjust this.
1285 When enabled with the default parameters, this option has
1286 almost no overhead, as it reserves a relatively small amount
1287 of memory and scans it infrequently. It both detects corruption
1288 and prevents it from affecting the running system.
1290 It is, however, intended as a diagnostic tool; if repeatable
1291 BIOS-originated corruption always affects the same memory,
1292 you can use memmap= to prevent the kernel from using that
1295 config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
1296 bool "Set the default setting of memory_corruption_check"
1297 depends on X86_CHECK_BIOS_CORRUPTION
1300 Set whether the default state of memory_corruption_check is
1303 config X86_RESERVE_LOW
1304 int "Amount of low memory, in kilobytes, to reserve for the BIOS"
1308 Specify the amount of low memory to reserve for the BIOS.
1310 The first page contains BIOS data structures that the kernel
1311 must not use, so that page must always be reserved.
1313 By default we reserve the first 64K of physical RAM, as a
1314 number of BIOSes are known to corrupt that memory range
1315 during events such as suspend/resume or monitor cable
1316 insertion, so it must not be used by the kernel.
1318 You can set this to 4 if you are absolutely sure that you
1319 trust the BIOS to get all its memory reservations and usages
1320 right. If you know your BIOS have problems beyond the
1321 default 64K area, you can set this to 640 to avoid using the
1322 entire low memory range.
1324 If you have doubts about the BIOS (e.g. suspend/resume does
1325 not work or there's kernel crashes after certain hardware
1326 hotplug events) then you might want to enable
1327 X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
1328 typical corruption patterns.
1330 Leave this to the default value of 64 if you are unsure.
1332 config MATH_EMULATION
1334 prompt "Math emulation" if X86_32
1336 Linux can emulate a math coprocessor (used for floating point
1337 operations) if you don't have one. 486DX and Pentium processors have
1338 a math coprocessor built in, 486SX and 386 do not, unless you added
1339 a 487DX or 387, respectively. (The messages during boot time can
1340 give you some hints here ["man dmesg"].) Everyone needs either a
1341 coprocessor or this emulation.
1343 If you don't have a math coprocessor, you need to say Y here; if you
1344 say Y here even though you have a coprocessor, the coprocessor will
1345 be used nevertheless. (This behavior can be changed with the kernel
1346 command line option "no387", which comes handy if your coprocessor
1347 is broken. Try "man bootparam" or see the documentation of your boot
1348 loader (lilo or loadlin) about how to pass options to the kernel at
1349 boot time.) This means that it is a good idea to say Y here if you
1350 intend to use this kernel on different machines.
1352 More information about the internals of the Linux math coprocessor
1353 emulation can be found in <file:arch/x86/math-emu/README>.
1355 If you are not sure, say Y; apart from resulting in a 66 KB bigger
1356 kernel, it won't hurt.
1360 prompt "MTRR (Memory Type Range Register) support" if EMBEDDED
1362 On Intel P6 family processors (Pentium Pro, Pentium II and later)
1363 the Memory Type Range Registers (MTRRs) may be used to control
1364 processor access to memory ranges. This is most useful if you have
1365 a video (VGA) card on a PCI or AGP bus. Enabling write-combining
1366 allows bus write transfers to be combined into a larger transfer
1367 before bursting over the PCI/AGP bus. This can increase performance
1368 of image write operations 2.5 times or more. Saying Y here creates a
1369 /proc/mtrr file which may be used to manipulate your processor's
1370 MTRRs. Typically the X server should use this.
1372 This code has a reasonably generic interface so that similar
1373 control registers on other processors can be easily supported
1376 The Cyrix 6x86, 6x86MX and M II processors have Address Range
1377 Registers (ARRs) which provide a similar functionality to MTRRs. For
1378 these, the ARRs are used to emulate the MTRRs.
1379 The AMD K6-2 (stepping 8 and above) and K6-3 processors have two
1380 MTRRs. The Centaur C6 (WinChip) has 8 MCRs, allowing
1381 write-combining. All of these processors are supported by this code
1382 and it makes sense to say Y here if you have one of them.
1384 Saying Y here also fixes a problem with buggy SMP BIOSes which only
1385 set the MTRRs for the boot CPU and not for the secondary CPUs. This
1386 can lead to all sorts of problems, so it's good to say Y here.
1388 You can safely say Y even if your machine doesn't have MTRRs, you'll
1389 just add about 9 KB to your kernel.
1391 See <file:Documentation/x86/mtrr.txt> for more information.
1393 config MTRR_SANITIZER
1395 prompt "MTRR cleanup support"
1398 Convert MTRR layout from continuous to discrete, so X drivers can
1399 add writeback entries.
1401 Can be disabled with disable_mtrr_cleanup on the kernel command line.
1402 The largest mtrr entry size for a continuous block can be set with
1407 config MTRR_SANITIZER_ENABLE_DEFAULT
1408 int "MTRR cleanup enable value (0-1)"
1411 depends on MTRR_SANITIZER
1413 Enable mtrr cleanup default value
1415 config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT
1416 int "MTRR cleanup spare reg num (0-7)"
1419 depends on MTRR_SANITIZER
1421 mtrr cleanup spare entries default, it can be changed via
1422 mtrr_spare_reg_nr=N on the kernel command line.
1426 prompt "x86 PAT support" if EMBEDDED
1429 Use PAT attributes to setup page level cache control.
1431 PATs are the modern equivalents of MTRRs and are much more
1432 flexible than MTRRs.
1434 Say N here if you see bootup problems (boot crash, boot hang,
1435 spontaneous reboots) or a non-working video driver.
1439 config ARCH_USES_PG_UNCACHED
1444 bool "EFI runtime service support"
1447 This enables the kernel to use EFI runtime services that are
1448 available (such as the EFI variable services).
1450 This option is only useful on systems that have EFI firmware.
1451 In addition, you should use the latest ELILO loader available
1452 at <http://elilo.sourceforge.net> in order to take advantage
1453 of EFI runtime services. However, even with this option, the
1454 resultant kernel should continue to boot on existing non-EFI
1459 prompt "Enable seccomp to safely compute untrusted bytecode"
1461 This kernel feature is useful for number crunching applications
1462 that may need to compute untrusted bytecode during their
1463 execution. By using pipes or other transports made available to
1464 the process as file descriptors supporting the read/write
1465 syscalls, it's possible to isolate those applications in
1466 their own address space using seccomp. Once seccomp is
1467 enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
1468 and the task is only allowed to execute a few safe syscalls
1469 defined by each seccomp mode.
1471 If unsure, say Y. Only embedded should say N here.
1473 config CC_STACKPROTECTOR
1474 bool "Enable -fstack-protector buffer overflow detection (EXPERIMENTAL)"
1476 This option turns on the -fstack-protector GCC feature. This
1477 feature puts, at the beginning of functions, a canary value on
1478 the stack just before the return address, and validates
1479 the value just before actually returning. Stack based buffer
1480 overflows (that need to overwrite this return address) now also
1481 overwrite the canary, which gets detected and the attack is then
1482 neutralized via a kernel panic.
1484 This feature requires gcc version 4.2 or above, or a distribution
1485 gcc with the feature backported. Older versions are automatically
1486 detected and for those versions, this configuration option is
1487 ignored. (and a warning is printed during bootup)
1489 source kernel/Kconfig.hz
1492 bool "kexec system call"
1494 kexec is a system call that implements the ability to shutdown your
1495 current kernel, and to start another kernel. It is like a reboot
1496 but it is independent of the system firmware. And like a reboot
1497 you can start any kernel with it, not just Linux.
1499 The name comes from the similarity to the exec system call.
1501 It is an ongoing process to be certain the hardware in a machine
1502 is properly shutdown, so do not be surprised if this code does not
1503 initially work for you. It may help to enable device hotplugging
1504 support. As of this writing the exact hardware interface is
1505 strongly in flux, so no good recommendation can be made.
1508 bool "kernel crash dumps"
1509 depends on X86_64 || (X86_32 && HIGHMEM)
1511 Generate crash dump after being started by kexec.
1512 This should be normally only set in special crash dump kernels
1513 which are loaded in the main kernel with kexec-tools into
1514 a specially reserved region and then later executed after
1515 a crash by kdump/kexec. The crash dump kernel must be compiled
1516 to a memory address not used by the main kernel or BIOS using
1517 PHYSICAL_START, or it must be built as a relocatable image
1518 (CONFIG_RELOCATABLE=y).
1519 For more details see Documentation/kdump/kdump.txt
1522 bool "kexec jump (EXPERIMENTAL)"
1523 depends on EXPERIMENTAL
1524 depends on KEXEC && HIBERNATION
1526 Jump between original kernel and kexeced kernel and invoke
1527 code in physical address mode via KEXEC
1529 config PHYSICAL_START
1530 hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
1533 This gives the physical address where the kernel is loaded.
1535 If kernel is a not relocatable (CONFIG_RELOCATABLE=n) then
1536 bzImage will decompress itself to above physical address and
1537 run from there. Otherwise, bzImage will run from the address where
1538 it has been loaded by the boot loader and will ignore above physical
1541 In normal kdump cases one does not have to set/change this option
1542 as now bzImage can be compiled as a completely relocatable image
1543 (CONFIG_RELOCATABLE=y) and be used to load and run from a different
1544 address. This option is mainly useful for the folks who don't want
1545 to use a bzImage for capturing the crash dump and want to use a
1546 vmlinux instead. vmlinux is not relocatable hence a kernel needs
1547 to be specifically compiled to run from a specific memory area
1548 (normally a reserved region) and this option comes handy.
1550 So if you are using bzImage for capturing the crash dump,
1551 leave the value here unchanged to 0x1000000 and set
1552 CONFIG_RELOCATABLE=y. Otherwise if you plan to use vmlinux
1553 for capturing the crash dump change this value to start of
1554 the reserved region. In other words, it can be set based on
1555 the "X" value as specified in the "crashkernel=YM@XM"
1556 command line boot parameter passed to the panic-ed
1557 kernel. Please take a look at Documentation/kdump/kdump.txt
1558 for more details about crash dumps.
1560 Usage of bzImage for capturing the crash dump is recommended as
1561 one does not have to build two kernels. Same kernel can be used
1562 as production kernel and capture kernel. Above option should have
1563 gone away after relocatable bzImage support is introduced. But it
1564 is present because there are users out there who continue to use
1565 vmlinux for dump capture. This option should go away down the
1568 Don't change this unless you know what you are doing.
1571 bool "Build a relocatable kernel"
1574 This builds a kernel image that retains relocation information
1575 so it can be loaded someplace besides the default 1MB.
1576 The relocations tend to make the kernel binary about 10% larger,
1577 but are discarded at runtime.
1579 One use is for the kexec on panic case where the recovery kernel
1580 must live at a different physical address than the primary
1583 Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
1584 it has been loaded at and the compile time physical address
1585 (CONFIG_PHYSICAL_START) is ignored.
1587 # Relocation on x86-32 needs some additional build support
1588 config X86_NEED_RELOCS
1590 depends on X86_32 && RELOCATABLE
1592 config PHYSICAL_ALIGN
1593 hex "Alignment value to which kernel should be aligned" if X86_32
1595 range 0x2000 0x1000000
1597 This value puts the alignment restrictions on physical address
1598 where kernel is loaded and run from. Kernel is compiled for an
1599 address which meets above alignment restriction.
1601 If bootloader loads the kernel at a non-aligned address and
1602 CONFIG_RELOCATABLE is set, kernel will move itself to nearest
1603 address aligned to above value and run from there.
1605 If bootloader loads the kernel at a non-aligned address and
1606 CONFIG_RELOCATABLE is not set, kernel will ignore the run time
1607 load address and decompress itself to the address it has been
1608 compiled for and run from there. The address for which kernel is
1609 compiled already meets above alignment restrictions. Hence the
1610 end result is that kernel runs from a physical address meeting
1611 above alignment restrictions.
1613 Don't change this unless you know what you are doing.
1616 bool "Support for hot-pluggable CPUs"
1617 depends on SMP && HOTPLUG
1619 Say Y here to allow turning CPUs off and on. CPUs can be
1620 controlled through /sys/devices/system/cpu.
1621 ( Note: power management support will enable this option
1622 automatically on SMP systems. )
1623 Say N if you want to disable CPU hotplug.
1627 prompt "Compat VDSO support"
1628 depends on X86_32 || IA32_EMULATION
1630 Map the 32-bit VDSO to the predictable old-style address too.
1632 Say N here if you are running a sufficiently recent glibc
1633 version (2.3.3 or later), to remove the high-mapped
1634 VDSO mapping and to exclusively use the randomized VDSO.
1639 bool "Built-in kernel command line"
1641 Allow for specifying boot arguments to the kernel at
1642 build time. On some systems (e.g. embedded ones), it is
1643 necessary or convenient to provide some or all of the
1644 kernel boot arguments with the kernel itself (that is,
1645 to not rely on the boot loader to provide them.)
1647 To compile command line arguments into the kernel,
1648 set this option to 'Y', then fill in the
1649 the boot arguments in CONFIG_CMDLINE.
1651 Systems with fully functional boot loaders (i.e. non-embedded)
1652 should leave this option set to 'N'.
1655 string "Built-in kernel command string"
1656 depends on CMDLINE_BOOL
1659 Enter arguments here that should be compiled into the kernel
1660 image and used at boot time. If the boot loader provides a
1661 command line at boot time, it is appended to this string to
1662 form the full kernel command line, when the system boots.
1664 However, you can use the CONFIG_CMDLINE_OVERRIDE option to
1665 change this behavior.
1667 In most cases, the command line (whether built-in or provided
1668 by the boot loader) should specify the device for the root
1671 config CMDLINE_OVERRIDE
1672 bool "Built-in command line overrides boot loader arguments"
1673 depends on CMDLINE_BOOL
1675 Set this option to 'Y' to have the kernel ignore the boot loader
1676 command line, and use ONLY the built-in command line.
1678 This is used to work around broken boot loaders. This should
1679 be set to 'N' under normal conditions.
1683 config ARCH_ENABLE_MEMORY_HOTPLUG
1685 depends on X86_64 || (X86_32 && HIGHMEM)
1687 config ARCH_ENABLE_MEMORY_HOTREMOVE
1689 depends on MEMORY_HOTPLUG
1691 config HAVE_ARCH_EARLY_PFN_TO_NID
1695 config USE_PERCPU_NUMA_NODE_ID
1699 menu "Power management and ACPI options"
1701 config ARCH_HIBERNATION_HEADER
1703 depends on X86_64 && HIBERNATION
1705 source "kernel/power/Kconfig"
1707 source "drivers/acpi/Kconfig"
1709 source "drivers/sfi/Kconfig"
1713 depends on APM || APM_MODULE
1716 tristate "APM (Advanced Power Management) BIOS support"
1717 depends on X86_32 && PM_SLEEP
1719 APM is a BIOS specification for saving power using several different
1720 techniques. This is mostly useful for battery powered laptops with
1721 APM compliant BIOSes. If you say Y here, the system time will be
1722 reset after a RESUME operation, the /proc/apm device will provide
1723 battery status information, and user-space programs will receive
1724 notification of APM "events" (e.g. battery status change).
1726 If you select "Y" here, you can disable actual use of the APM
1727 BIOS by passing the "apm=off" option to the kernel at boot time.
1729 Note that the APM support is almost completely disabled for
1730 machines with more than one CPU.
1732 In order to use APM, you will need supporting software. For location
1733 and more information, read <file:Documentation/power/pm.txt> and the
1734 Battery Powered Linux mini-HOWTO, available from
1735 <http://www.tldp.org/docs.html#howto>.
1737 This driver does not spin down disk drives (see the hdparm(8)
1738 manpage ("man 8 hdparm") for that), and it doesn't turn off
1739 VESA-compliant "green" monitors.
1741 This driver does not support the TI 4000M TravelMate and the ACER
1742 486/DX4/75 because they don't have compliant BIOSes. Many "green"
1743 desktop machines also don't have compliant BIOSes, and this driver
1744 may cause those machines to panic during the boot phase.
1746 Generally, if you don't have a battery in your machine, there isn't
1747 much point in using this driver and you should say N. If you get
1748 random kernel OOPSes or reboots that don't seem to be related to
1749 anything, try disabling/enabling this option (or disabling/enabling
1752 Some other things you should try when experiencing seemingly random,
1755 1) make sure that you have enough swap space and that it is
1757 2) pass the "no-hlt" option to the kernel
1758 3) switch on floating point emulation in the kernel and pass
1759 the "no387" option to the kernel
1760 4) pass the "floppy=nodma" option to the kernel
1761 5) pass the "mem=4M" option to the kernel (thereby disabling
1762 all but the first 4 MB of RAM)
1763 6) make sure that the CPU is not over clocked.
1764 7) read the sig11 FAQ at <http://www.bitwizard.nl/sig11/>
1765 8) disable the cache from your BIOS settings
1766 9) install a fan for the video card or exchange video RAM
1767 10) install a better fan for the CPU
1768 11) exchange RAM chips
1769 12) exchange the motherboard.
1771 To compile this driver as a module, choose M here: the
1772 module will be called apm.
1776 config APM_IGNORE_USER_SUSPEND
1777 bool "Ignore USER SUSPEND"
1779 This option will ignore USER SUSPEND requests. On machines with a
1780 compliant APM BIOS, you want to say N. However, on the NEC Versa M
1781 series notebooks, it is necessary to say Y because of a BIOS bug.
1783 config APM_DO_ENABLE
1784 bool "Enable PM at boot time"
1786 Enable APM features at boot time. From page 36 of the APM BIOS
1787 specification: "When disabled, the APM BIOS does not automatically
1788 power manage devices, enter the Standby State, enter the Suspend
1789 State, or take power saving steps in response to CPU Idle calls."
1790 This driver will make CPU Idle calls when Linux is idle (unless this
1791 feature is turned off -- see "Do CPU IDLE calls", below). This
1792 should always save battery power, but more complicated APM features
1793 will be dependent on your BIOS implementation. You may need to turn
1794 this option off if your computer hangs at boot time when using APM
1795 support, or if it beeps continuously instead of suspending. Turn
1796 this off if you have a NEC UltraLite Versa 33/C or a Toshiba
1797 T400CDT. This is off by default since most machines do fine without
1801 bool "Make CPU Idle calls when idle"
1803 Enable calls to APM CPU Idle/CPU Busy inside the kernel's idle loop.
1804 On some machines, this can activate improved power savings, such as
1805 a slowed CPU clock rate, when the machine is idle. These idle calls
1806 are made after the idle loop has run for some length of time (e.g.,
1807 333 mS). On some machines, this will cause a hang at boot time or
1808 whenever the CPU becomes idle. (On machines with more than one CPU,
1809 this option does nothing.)
1811 config APM_DISPLAY_BLANK
1812 bool "Enable console blanking using APM"
1814 Enable console blanking using the APM. Some laptops can use this to
1815 turn off the LCD backlight when the screen blanker of the Linux
1816 virtual console blanks the screen. Note that this is only used by
1817 the virtual console screen blanker, and won't turn off the backlight
1818 when using the X Window system. This also doesn't have anything to
1819 do with your VESA-compliant power-saving monitor. Further, this
1820 option doesn't work for all laptops -- it might not turn off your
1821 backlight at all, or it might print a lot of errors to the console,
1822 especially if you are using gpm.
1824 config APM_ALLOW_INTS
1825 bool "Allow interrupts during APM BIOS calls"
1827 Normally we disable external interrupts while we are making calls to
1828 the APM BIOS as a measure to lessen the effects of a badly behaving
1829 BIOS implementation. The BIOS should reenable interrupts if it
1830 needs to. Unfortunately, some BIOSes do not -- especially those in
1831 many of the newer IBM Thinkpads. If you experience hangs when you
1832 suspend, try setting this to Y. Otherwise, say N.
1836 source "arch/x86/kernel/cpu/cpufreq/Kconfig"
1838 source "drivers/cpuidle/Kconfig"
1840 source "drivers/idle/Kconfig"
1845 menu "Bus options (PCI etc.)"
1850 select ARCH_SUPPORTS_MSI if (X86_LOCAL_APIC && X86_IO_APIC)
1852 Find out whether you have a PCI motherboard. PCI is the name of a
1853 bus system, i.e. the way the CPU talks to the other stuff inside
1854 your box. Other bus systems are ISA, EISA, MicroChannel (MCA) or
1855 VESA. If you have PCI, say Y, otherwise N.
1858 prompt "PCI access mode"
1859 depends on X86_32 && PCI
1862 On PCI systems, the BIOS can be used to detect the PCI devices and
1863 determine their configuration. However, some old PCI motherboards
1864 have BIOS bugs and may crash if this is done. Also, some embedded
1865 PCI-based systems don't have any BIOS at all. Linux can also try to
1866 detect the PCI hardware directly without using the BIOS.
1868 With this option, you can specify how Linux should detect the
1869 PCI devices. If you choose "BIOS", the BIOS will be used,
1870 if you choose "Direct", the BIOS won't be used, and if you
1871 choose "MMConfig", then PCI Express MMCONFIG will be used.
1872 If you choose "Any", the kernel will try MMCONFIG, then the
1873 direct access method and falls back to the BIOS if that doesn't
1874 work. If unsure, go with the default, which is "Any".
1879 config PCI_GOMMCONFIG
1896 depends on X86_32 && PCI && (PCI_GOBIOS || PCI_GOANY)
1898 # x86-64 doesn't support PCI BIOS access from long mode so always go direct.
1901 depends on PCI && (X86_64 || (PCI_GODIRECT || PCI_GOANY || PCI_GOOLPC))
1905 depends on X86_32 && PCI && (ACPI || SFI) && (PCI_GOMMCONFIG || PCI_GOANY)
1909 depends on PCI && OLPC && (PCI_GOOLPC || PCI_GOANY)
1913 depends on PCI && XEN
1921 bool "Support mmconfig PCI config space access"
1922 depends on X86_64 && PCI && ACPI
1924 config PCI_CNB20LE_QUIRK
1925 bool "Read CNB20LE Host Bridge Windows"
1928 Read the PCI windows out of the CNB20LE host bridge. This allows
1929 PCI hotplug to work on systems with the CNB20LE chipset which do
1933 bool "Support for DMA Remapping Devices (EXPERIMENTAL)"
1934 depends on PCI_MSI && ACPI && EXPERIMENTAL
1936 DMA remapping (DMAR) devices support enables independent address
1937 translations for Direct Memory Access (DMA) from devices.
1938 These DMA remapping devices are reported via ACPI tables
1939 and include PCI device scope covered by these DMA
1942 config DMAR_DEFAULT_ON
1944 prompt "Enable DMA Remapping Devices by default"
1947 Selecting this option will enable a DMAR device at boot time if
1948 one is found. If this option is not selected, DMAR support can
1949 be enabled by passing intel_iommu=on to the kernel. It is
1950 recommended you say N here while the DMAR code remains
1953 config DMAR_BROKEN_GFX_WA
1954 bool "Workaround broken graphics drivers (going away soon)"
1955 depends on DMAR && BROKEN
1957 Current Graphics drivers tend to use physical address
1958 for DMA and avoid using DMA APIs. Setting this config
1959 option permits the IOMMU driver to set a unity map for
1960 all the OS-visible memory. Hence the driver can continue
1961 to use physical addresses for DMA, at least until this
1962 option is removed in the 2.6.32 kernel.
1964 config DMAR_FLOPPY_WA
1968 Floppy disk drivers are known to bypass DMA API calls
1969 thereby failing to work when IOMMU is enabled. This
1970 workaround will setup a 1:1 mapping for the first
1971 16MiB to make floppy (an ISA device) work.
1974 bool "Support for Interrupt Remapping (EXPERIMENTAL)"
1975 depends on X86_64 && X86_IO_APIC && PCI_MSI && ACPI && EXPERIMENTAL
1977 Supports Interrupt remapping for IO-APIC and MSI devices.
1978 To use x2apic mode in the CPU's which support x2APIC enhancements or
1979 to support platforms with CPU's having > 8 bit APIC ID, say Y.
1981 source "drivers/pci/pcie/Kconfig"
1983 source "drivers/pci/Kconfig"
1985 # x86_64 have no ISA slots, but do have ISA-style DMA.
1994 Find out whether you have ISA slots on your motherboard. ISA is the
1995 name of a bus system, i.e. the way the CPU talks to the other stuff
1996 inside your box. Other bus systems are PCI, EISA, MicroChannel
1997 (MCA) or VESA. ISA is an older system, now being displaced by PCI;
1998 newer boards don't support it. If you have ISA, say Y, otherwise N.
2004 The Extended Industry Standard Architecture (EISA) bus was
2005 developed as an open alternative to the IBM MicroChannel bus.
2007 The EISA bus provided some of the features of the IBM MicroChannel
2008 bus while maintaining backward compatibility with cards made for
2009 the older ISA bus. The EISA bus saw limited use between 1988 and
2010 1995 when it was made obsolete by the PCI bus.
2012 Say Y here if you are building a kernel for an EISA-based machine.
2016 source "drivers/eisa/Kconfig"
2021 MicroChannel Architecture is found in some IBM PS/2 machines and
2022 laptops. It is a bus system similar to PCI or ISA. See
2023 <file:Documentation/mca.txt> (and especially the web page given
2024 there) before attempting to build an MCA bus kernel.
2026 source "drivers/mca/Kconfig"
2029 tristate "NatSemi SCx200 support"
2031 This provides basic support for National Semiconductor's
2032 (now AMD's) Geode processors. The driver probes for the
2033 PCI-IDs of several on-chip devices, so its a good dependency
2034 for other scx200_* drivers.
2036 If compiled as a module, the driver is named scx200.
2038 config SCx200HR_TIMER
2039 tristate "NatSemi SCx200 27MHz High-Resolution Timer Support"
2043 This driver provides a clocksource built upon the on-chip
2044 27MHz high-resolution timer. Its also a workaround for
2045 NSC Geode SC-1100's buggy TSC, which loses time when the
2046 processor goes idle (as is done by the scheduler). The
2047 other workaround is idle=poll boot option.
2050 bool "One Laptop Per Child support"
2052 select OLPC_OPENFIRMWARE
2054 Add support for detecting the unique features of the OLPC
2058 tristate "OLPC XO-1 support"
2059 depends on OLPC && PCI
2061 Add support for non-essential features of the OLPC XO-1 laptop.
2063 config OLPC_OPENFIRMWARE
2064 bool "Support for OLPC's Open Firmware"
2065 depends on !X86_64 && !X86_PAE
2068 This option adds support for the implementation of Open Firmware
2069 that is used on the OLPC XO-1 Children's Machine.
2070 If unsure, say N here.
2076 depends on CPU_SUP_AMD && PCI
2078 source "drivers/pcmcia/Kconfig"
2080 source "drivers/pci/hotplug/Kconfig"
2085 menu "Executable file formats / Emulations"
2087 source "fs/Kconfig.binfmt"
2089 config IA32_EMULATION
2090 bool "IA32 Emulation"
2092 select COMPAT_BINFMT_ELF
2094 Include code to run 32-bit programs under a 64-bit kernel. You should
2095 likely turn this on, unless you're 100% sure that you don't have any
2096 32-bit programs left.
2099 tristate "IA32 a.out support"
2100 depends on IA32_EMULATION
2102 Support old a.out binaries in the 32bit emulation.
2106 depends on IA32_EMULATION
2108 config COMPAT_FOR_U64_ALIGNMENT
2112 config SYSVIPC_COMPAT
2114 depends on COMPAT && SYSVIPC
2119 config HAVE_ATOMIC_IOMAP
2123 config HAVE_TEXT_POKE_SMP
2125 select STOP_MACHINE if SMP
2127 source "net/Kconfig"
2129 source "drivers/Kconfig"
2131 source "drivers/firmware/Kconfig"
2135 source "arch/x86/Kconfig.debug"
2137 source "security/Kconfig"
2139 source "crypto/Kconfig"
2141 source "arch/x86/kvm/Kconfig"
2143 source "lib/Kconfig"
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